Telephone system



Nov. 24, 1925- 1,562,528

J. F. TOOMEY ET/AL TELEPHONE SYSTEM Filed NQV. 15, 1923 4 Sheets-Sheet 1hyerrio/a: Jam f 700/226 flew 5 Pie/pa Nov. 24,1925 1,562,528

J. F. TOOMEY. ET AL TELEPHONE SYSTEM giled Nov. 15. 1923 4 Sheets-Sheet2 Nov. 24, 1925- J. F. TOOMEY El AL TELEPHONE SYSTEM Filed NOV. 15. 19234 Sheets-Sheet 5 hue/1mm. Jo/mfl' 7'0omey Hen/315 Pheks by Nov. 24,1925. 1 1,562,528

J. F. TQOMEY ET AL TELEPHONE SYSTEM Flled Nov. 15 1923 4 Sheets-Sheet 4Patented Nov. 24, 1925.

warren: stare rare NQT Farce,

JOHN F. TooMEy Am) HENRYLE, PHELPS, or yortrnn, Y,, .a ssronoas; 12oAnnexcan TELEPHONE 1am) :TELEGBAI H zooiarAnmn oonronnmron, or 3TELEPHONE rsrrala Applipat ion filed November 15, 1923-. Serial No.674,939.

T0 all whom it may concern:

Be it known that we, JoH1 I. F. TOOMEY and HENRY E. PHELPS, residing atNew- York and New York, in the counties, ofNew York and Bronx,andstatetof New Yorlo and New York, have invented certaihIniprovements111 Telephone systems oi' which the following is R SPQCIfiQQlIIOD.

This 7 invention relates to {telephone sys terns, and more part cularly,to' systems feature or the lllYBIllQl-Oll by providing manualswitchboard operators with cord less connecting circuits, that is,i'nsteagtl er;

providing the-operator with av number of cordsand jacks with whichsheinay coin: plete connections, each position is equipped with keysets, each set comprising a pie rality of mechanically interlocking keysin which the connecting circuits serving that By this arrangement themere act. of operating-a, key hy an lop erator extends a call incomingto her post position terminate.

tion tothe positionor. switchboard corre sponding tothe key actuated.Cordless connecting cllClllts are part cularly adapted for use at what,are known as recording operators positions.

Another feature of, the invention resides in the automatic distributionof callsinconiL mg to a recording operatofls, pos t on.

W hen a recording trunk. is taken up at its outgoing end for a new call,itsinco-n' ing end is automatically connected to an idle recordingoperator, by means of a rotary, type select-or swltch. The l ghting ofa.

lamp signal indicates to the recording op orator that a call has come 1nonone other,v

idle connecting circuits.

A further feature of the invent on resides The operation of talking keyunit of, a connecting key set at arecording operators position completesa circuit for indicating. to.

therecording operator the [calling subscribe crs class of SGFV1C8.,

A still further: feature residesin the auto:

matic selection of trunks -.terminating; at the recording operatorsposition In case a call incoining to a recording operato'rsposi ti-on isof such a nature thattherecording operator inust extendit to some otherpart ofithe ofli'ce, she may do so by operating the proper-nnitot aconnecting key set and an idle trunk'leadinglto the desired positionorde'skf, will then be "automatically selected by a rotary;typeselectorswitch; U

Another feature residesfin the prevention of intrusion on a busyopera-tor. When recording operator actuates' 'altalking key" in responseto I an incoming call all th'e'icon neoting' circuits seryingthatposition are rendered busy; so [that "new "call's are excludedduringcthe time the operator is completing the first connection. A

The above and other features of the inventionwill readilyappear'fMriith'e following detailed description madefwith [reference to.the accompanying drawings inv which Figure 1 shows the outgoing end ofa; toll trunk line terminating in a semi inecha'nioal oiiice to getherwith the associated apparatusior transmitting class or service signalsover the trunk line, a calling subscribefls line and a diagrammaticrepresentation of the circuits of a semi-mechanical operatorsposition]for,,

extending a connection from the s ubscriber s lineftoithe toll trunk."Fig, 2 shows the incoming end of the toll trunk line together with thenecessary equipment for relaying the class of service signals; and aselector switch in whichthe' cordless connecting circuits leading torecording ope1'ato1l*s "positions terminate; Fig 8 shows'a connectingcircuit terminating in a plurality of keys at a recording "operatorsposition" "some of which areemployed in extending an incom ing call toanother position such as the soconnecting circult, appearing betoreanidle,

called ratequotingT pOsitiOnM by way of the, rotary type selector switchK. The equipment necessary for receiving the class of service signals isal'so shown in Fig, 3. Fig. 4 shows the outgoing end ot a tolltrunk lineterminating-in a manual ofiice and the I necessary equipment at thatoffice for transin the provision of class of service signals,

n itting class of; service signals-over the toll trunk line. This figurecorresponds to the arrangement showninFig 1,

The following description will trace a call from the originatingsubscribers line A over the toll trunk line B, by We}? Ofaseminiec'hanical office, to the recordingoperators position 0, Fig. 3.Thence the call is ex tended to a special operators position M. Thoughthe following description is directed to a call'handled by asemi-mechanical operator, it is obvious that the multiple terminal shownin Fig. 1 may be seized by a mechanical subscribers machine switchingequipment direct, the choice of terminals being dictated by conditionsinserted in the subscribers line equipment.

A calling subscriber at A to initiate a call removes the receiver fromthe switchhook thereby closing the circuit of the line relay 30. Thiscircuit extends from grounded battery, through the left-hand winding ofrelay 30, the outer armature and back contact of cut-01f relay 31,thence over the subscribers line loop and through the back contact andinner armature of relay 31, to ground, through the right-hand winding ofrelay 30. Relay 30 energizes in this circuit and closes an obviouscircuit for line lamp 32. This line lamp is provided with a distinctivelamp cap 32 which enables the answering operator to determine the classof service to which the calling subscriber is entitled. In the presentcase it will be assumed that the calling subscriber is entitled toregular toll service.

The semi-mechanical operator on noting the illumination of lamp 32inserts the answering plug P of an idle cord circuit at her position inthe jack J of the calling line whereupon a circuit is established overthe sleeve contacts of the plug and jack J, through the win-ding ofcut-off relay 31, which relay operates and opens'the circuit of linerelay 30 thereby extinguishing the line lamp 32.

The operator now obtains from the calling subscriber the nature of theconnection desired, and assuming that the subscriber desires a tollconnection, the operator proceeds to set up on her sender X,the'necessary code for settingthe brushes of the district selector 90,in which her cord circuit terminates, upon the terminals of a toll trunkline extending to the recording operators position at O, Fig. 3. Thecode which the semi-mechanical operator'sets up upon her keyboard isalso determined by the class of service to which the calling subscriberis entitled and therefore the brushes of district selector will not onlybe set, by the sender X, upon the terminals of the toll trunk line butalso upon a particular set of multiple terminals of the toll trunk linefor causing the transmission thereover, of a special distinctive'signalto inform the toll operator of the class of service to which the callingsubscriber, is entitled For this purpose each toll trunk line terminatesat the terminal bank of the district selector 90"in four sets ofterminals. In the case assumed the brushes of the district selcctor 9Owill be set upon the first set of terminals 9, 10 and 11. A circuit isthereupon established which may be traced from grounded batter throughthe lower lefthand winding'of repeating coil 12, winding of relay 13,upper normal contacts of relay 14, terminal 11 and the associated brushof the district selector 90, the left-hand normal contacts of key K,through the windings of the polarized supervisory relay 91, righthandnormal contacts of key K, brush and terminal 10 of the district selector90, lower normal contacts of relay 14, through the upper left-handwinding of repeating coil 12, to ground. The direction of current inthis circuit is such as to permit relay 91 to operate causing an obviouscircuit for the supervisory lamp 92 to be established. The illuminationof lamp 92 at this time serves as a guard signal. Relay 13 also operatesin this circuit and establishes a circuit extending from groundedbattery, through the winding of relay 15, and winding of relay 16, toground, over the front contact and armature of relay 13. Relays 15 and16 operate in this circuit. Relay 16 at its inner armature prepares acircuit for the reversing relay 14, the purpose of which will bedescribed at a later time. At its outer armature relay 16 prepares acircuit originating at the positive pole of battery 70 which circuitwill be completed presently. Relay 15 operating in series with relay 16establishes an obvious circuit for the slowto-release relay 19. Relay 19at its righthand armature establishes an obvious circuit forsloW-to-release relay 20 and at its lefthand armature removes the shortcircuit from the left-hand armature contacts of relay 15.

The circuit originally started by the attraction of the outer armatureof relay 16 is now complete and may be traced from grounded battery 70,resistance elements 17 and 18, conductor 21, front contact and outerarmature of relay 16, conductors 22 and 23, back contacts and armatureof slow-to-operate relay 24, left-hand armature and front contact ofslow-to-release relay 20, left-hand armature and front contact of relay15, winding of marginal relay 25, lower righthand winding of repeatingcoil 12, conductor 95, lower left-hand winding of repeating coil 103,through the windings of polarized relay 102, marginal relay 101 andrelay 100, upperleft-hand winding of re peating coil 103, conductor 96,through the upper right-hand winding of repeating coil 12, to ground.Relay 25 being marginal does not operate in this circuit.

The current in the circuit just traced is in such a direction and ofsuch strength as to operate only relay 100 of relays 100, 101 and 102which are bridged across the trunk conductors and 96 through theleft-hand iii) windings of repeating coil 103; Relay 100 in operatingestablishes an obvious circuit for relay 1. Relay 104 operates, and inattracting its outer armature establishes circuits for relays 105 and100 the former extending from grounded battery, through the winding ofrelay 105, normal contacts of hand arn'iature and back contact of relay109, through the winding 01. relay 112 to ground. Relay 112-, operatingin this circuit, connects a source of tone current 113 to the mainconductors of the trunk to indicate to the calling subscriber that therecording operatoris being signaled as will appear presently.

Relay 105, operating in the circuit hereinbefore traced, establishes acircuit extending from ground, through positive pole or the battery 114,resistance elements 115 and 116, back contact and outer right-handarmature of relay 117, conductor 118, back contact and outer right-handarmature of relay 119, conductor 120, righthand armature and frontcontact of relay 105, conductor 121, to the mid-point of the right-handwindings ot repeating coil 108 and thence over the tip and ringconductors of the trout: as far as the arniatures of relay 122. Thiscircuit will be completed presently. At its lefthand armature relay 105establishes a locking circuit for itself extending from groundedbattery, through the winding of relay 105, front contact and leftha-ndarmature of re lay 105, conductor 128, conductor 108, normal contactsoft relay 109, conductor 110, over the front contact and righthandarniature of relay 104, to ground.

Relay 100 operating in the circuit previously traced, causes the steppinmagnet 12% to energize in a circuit extending from grounded battery,through the IQSiSAiDCQ element 125, winding and armature and backcontact of magnet 124;, armature and back contact oi? relay 107, botharniatnrcsand front contacts of relay 100, right-hand winding of relay100, through both windings of relay 107 to ground. The stepping in. net124, operating in this circuit, causes the selector switch S to starthunting for an idle trunk leading to the recording operations position.As soon as the test wiper 120 of switch S encounters a contact which issupplied with battery, that is an idle trunk, the stepping magnet ceasesto operate since it is shunted by the battery 200 (Fig. associated withthe idle trunk. Relay 107 now operates in a circuit e:-;tending fromgrounded battery 200, through the resistance element 201, back contactand left-hand armature of relay 203, back contact and armature of relay1, upper contact 01 key 205, conductor 200, contact 127' and wiper 120of the selector switch S, front contact and inner arniatnre of relay106, therighthand winding of relay 100, through both windings of relay107, to ground. Relay 10? in attracting its right-hand armature opensthe original circuit of stepping mag net 12th it its outer left-handarmature relay 10? 'ranst'ers the ground received from the make contactof relay 10 1 from the win-ding o1 relay 100 to the winding of relay 1Relay 122 thereupon operates connecting the tip and ring conductorsotthe-trunl: to corresponding terminals of the selector switch S. At itstwo lower arinatures relay 122 connects conductors 128 and 129 to thewindings oil? relays 107 and 133 for pun poses which will hereinafterappear. A circuit tor relay 203 now exists which may be,

traced from grounded battery, hrough the winding of relay 203, conductor202, terminal 130 and wiper 131 of switch S, conductor 128, frontcontact and lowermost arinature of relay 122, leit't-hand inner armatureand contact of relay 102', through the right-hand winding of relay 10?,to ground. Relay 208 in attracting its left-hand armature removesbattery 200 from the test terininal 12'? of switch S and substitutes aground therefor, in order to hold the inult-iplecontacts out otherselector switches busy. At its right-hand armature, relay 203establishes a circuit extending from grounded battery, over theright-lnind armature and front contact GTE relay 203, back contact andinner left-hand armature of relay 207, lefthand arinatrure and backcontact of relay 208, through the filament of lamp 20.0, to ground. Theillumination of lamp 200 in this circuit indicates to the recordingoperator that there is a. call awaiting her atten tion and she proceedsto answer it in the following manner.

It is to be understood that relay 10, re mains operated in series withrelay 203. Too recording operator in response to the illumination oflamp 209 actuates the tails ing lrey 210, whereupon a circuit isestablished extending from grounded battery. through the winding ofrelay 207, to ground on the lower alternate contacts of lacy 210. Relay20?. operates in this circuit and performs the following functions: Atits outer right-hand armature, it connects ground to the contact ofswitch S by way of the.

normal contact of key 211, which ground hereinafter to be described.

. 204 in a. circuit connected to battery through the windings of allother such relays that are located in. the connecting circuits to whichthis operator has access. All these relays will, therefore, operate andconnect ground to the test terminals of these connecting circuits at allselector switches associated therewith and thereby causing saidconnecting circuits to test busy as long as any key, such as 210, at anyone of the connecting circuits at this operators position is operated.It is therefore evident that a position will not be selected by anyincoming call as long as the operator at that position has one of hertalking keys thrown. That is, any relay 207 which is operated causes theoperation of all relays 204, as the lead from the inner contact of theouter left hand armature of these relays are multiplied together, asindicated by the taps on this lead. At its middle and upper alternatecontacts key 210 bridges the operators telephone set and the simplexcircuit including the windings of relay 214, marginal relay 215 andpolarized relay 216 across the tip and ring conductors of the trunk.

Upon the connection of ground to the contact 132 of selector switch S ashereinbefore described, Frelay 133 operates and at its right-handarmature establishes an obvious circuit for relay 109, while at itsleft-hand armature it short circuits the high resistance left-handwinding of relay 100. The shunting of the high resistance winding ofrelay 100 causes an increase in current in the circuit including thewinding of marginal relay hereinbefore traced. Marginal relay 25thereupon operates and establishes an obvious circuit for relay 60.Relay 60 in attracting its left-hand armature establishes a newenergizing circuit for slow-to-release relay 20 which may be traced fromgrounded battery, through the winding of slow-to-release relay 20,conductor 61, over the front contact and left-hand armature of relay 60,to ground. At its right-hand armature relay 60 establishes an obviouscircuit for slowto-release relay 63, and also a circuit for thereversing relay 14 which may be traced from grounded battery, throughthe winding of relay 14, front contact and inner armature of relay 16,conductor 64, armature and back contact of relay 65, conductor 66, overthe front contact and right-hand armature of relay 60, to ground. Relay14 operates in this circuit and in attracting its armatures reverses thetip and ring conductors of the trunk so that the current from thebattery associated with the repeating coil 12 is reversed through thewindings of polarized relay 91 so that this relay releases to extinguishthe supervisory lamp 92. The darkening of lamp 92 at this time is of noimportance as the semi-mechanical operator does not attend further tothe connection, unless she is recalled by the calling subscriber, untilshe receives the disconnect signal.

Relay 63 which operated as a result of the energization of relayestablishes an obvious circuit for relay 67 which thereupon operates andlocks to ground on the righthand armature of relay 20. In attracting itsright-hand armature, relay 67 performs no useful function at this timesince the circuit for interrupter 80 is opened at the back contact ofrelay 63. Since relay 20 is now maintained energized over two circuits,one indirectly controlled by relay 13 in the outgoing end of the tolltrunk, and the other indirectly controlled by relay 133 in the incomingend of the toll trunk, the locking circuit for relay 67 is thereforemaintained as long as the trunk is held in service at either of itsends, and therefore ground potential is maintained on all multiples oftest terminal 9 appearing in all district selectors having access to theoutgoing end of the toll trunk. This ground is connected to the testterminal 9 in a circuit extending over conductor 68 to ground on themiddle left-hand ill!) armature and front contact of relay 67. The tolltrunk is thus made unavailable to other outgoing calls until after ithas been released at both its ends. Relay 67 at its outer lefthandarmature establishes an obvious circuit for relay 24 which operates,disconnecting battery 70 from the winding of marginal relay 25 andsubstituting therefor the battery associated with the front contact ofrelay 24, in order to hold relays 25 and operated.

Relay 109 operating as a consequence of the operation of relay 133 ashereinbefore described, locks up over its outer left-hand armature tobattery on the inner right-hand armature of relay 104. At its inner lefthand armature relay 109 prepares a circuit for relay 134, the purpose ofwhich will hereinafter be described- At its right-hand armature relay109 connects ground to the windings of relays 122 and holding themoperated independently of relay 104. In opening its left-hand normalcontact, relay 109 opens the circuit for relay 112 which thereuponreleases removing the tone source 113 from the trunk, which serves as anindication to the calling'subscriber that the recording toll operatorhas answered the call and also removing ground from the armatures ofrelays 101 and 102.

As a consequence of the various operations Cit hereinbefore described, acircuit now exists which may be traced from ground,'through battery114., resistance elements 115'and 116, back contact and outer rightdiandarmature of relay 117, conductor 118, back contact and right-handarmature of relay 119, conductor 120, right-hand armature and frontcontact of relay 105, conductor 121, and thence in parallel through theright-hand windings of repeating coil 103, back contacts and armaturesof relay 134, upper and innermost lower armatures and front contacts ofrelay 122, wipers 138 and 139, and terminals 140 and 141 of switch S,middle and upper alternate contacts of key 210, through the simplexwindings 217. and 218, through the windings of relay 214, marginal relay215 and polarized relay 216, to ground. The current in this circuitbeing of such a'polarity and of a relatively low Value does not causeeither marginal relay 215 or polarized relay 216 to operate. Relay 214,however, operates causing lamp 219 toglow in a circuit extending fromgrounded battery, through the filament of lamp 219, back contact andleft hand armature of marginal relay 215, back contact and armature ofpolarized relay 216, over the armature and front contact of relay 214,to ground. The illumination of lamp 219 which is provided with a cap 219having a distinguishing marking corresponding to the marking on lamp 32,inclicates to the recording operator the class of service to which thisparticular calling subscribers line is entitled.

Since the operators telephone set is bridged across the main conductorsof the connection by the actuation of key 210, the recording operatormaynow converse with the calling subscriber. It will 'be assumed that thesubscriber desires a connection with some o )erating room desk such asthe rate quoting desk and that such a request is made to the recordingoperator. The operator may'then restore her talking key 210 and actuatethe rate quoting key 220. The actuation of key 220 causes cut-off relay203 to operate in a circuit extending from grounded battery, through thewinding of relay 208, conductor 221, to ground over the u crmostalternate contact of key 220. Relay 203 at its left-hand armature cutsoff the lamp 209 and at its right-hand armature applies ground tothe'terminal 132 by way of the lead 212 to hold busy the equipment inthe recording trunk circuit. At its two inner alternate contacts key 220prepares the tip and ring conductors of the connecting circuit forconnectionwith the corresponding terminals of the selector switch K. Atits lowermost alternate contact, key 2-20establishes an obvious circuitfor relay r222. Relay 222 operates in this circuit and connects groundto the winding ground.

of relay 223 and also to conductor 224. It will be noted that sector 228of the switch K has itsterminals'divided into four groups, with acertain nuniber of terminals allotted to each group'and each groupcorresponding to one of the keys 227, 220, 226 and 225. 'if he terminalsof the sector'228 are allotted in accordance with the tralfic, that is,calls for information "being more numerous than calls for rate quoting,for chief operator or for directory, a greater number oftermina'lswillbe assigned to information 'than to the other desks. The informationdesk group of'terminals obyiously corresponds to key 225, whereas thekey 226 corresponds to the chief operator desk group of terminals, key220 corre sponds to'the rate-quoting desk group of terminals and key 227corresponds to the directory desk group ofterminals. The grounding ofconductor 224 by relay 222 connects gro'undto the group of terminals 230which is allotted to rate quoting. The operation of relay 223 ashereinbefore described causes the stepping magnet 231 to energize in acircuit extending from grounded battery, through the resistance elementwinding of magnet'231, armature and back contact of magnet 231,conductor 233, back Contact andle ft -hand armature of relay L34,conductor 235, over the front contact and outer armature of relay 223,to ground. At its inner armature relay 223 prepares a circuit for'relay270 aswill hereinafter appear. The stepping magnet231 upon energizing,causes the selector switch K to step around until the group of ground edterminals 230 is reached, whereupon relay 234 energizes in a circuitextending from grounded battery, through the winding of relay 234-,right-hand normal contacts of relay 234, conductor 236, Wiper'237 ofswitch K,'to ground on the group of contacts 230. Relay z34 operates andlocks itself to ground on the outer armature of relay and disconnectsitself from the wiper 237 of switch K. At its left-hand armature relay234 causes relay 238 to operate in a circuit which may be traced fromgrounded battery, through the left hand winding of relay 238, backcontact and outer left-hand armature of relay 239,1'1101'1t contact andleft-hand armature of relay 234, conductor 235, front contact and outerarmature of relay 223, to In completing this circuit relay 234 openstheoriginal energizing'circuit for stepping magnet 231. Relay 238 inoperating establishes a circuit extending from grounded battery, throughthe resistance clement232, winding of magnet 231, armature-and backcontact of -magnet231,outer right-hand armature and back contact ofrelay 239, outer. armature andfront contact .of relay 238,"fr.ontcontact and inner arma- Lure of relay 238, {gilt-hand winding 01 relay238,'to ground, through both windings 7 contact and left-hand armatureof relay 270,

of relay 239. Owing to theinclusion of re slstance element 232 in thiscircuit relay 239 does not receive sufficient current to operate at thistime. .The stepping magnet 231,

however, operates and causes the selector switch K to hunt for an idletrunk in the group corresponding to the group of terminals 230 leadingto the rate quoting desk. The idle condition of the trunk is indicatedby the presence of battery on the test terminal 242. vAs soon as such anidle trunk such as L is encountered a circuit is established extendingfrom grounded battery, through the resistance element 240, back normalcontact of key 241, test terminal 242 and wiper 243 of switch K,conductor 244,

front contact and inner armature of relay 238, right-hand wmdmg of relay238, to ground, through both windings of relay 239.

The battery associated with the resistance element 240 shunts out thestepping magnet 231 causing it to release. The current through thewindings of relay 239 is sulficient now to causethis relay to operateand lock up in series with relay 270 in a circuit extending fromgrounded battery, through the winding of relay 270, terminal 245 andwiper 246 of switch K, conductor 247, front contact and inner armatureof relay inner left-hand armature and front contact of relay 239,right-hand winding of relay 239 to ground. Relay 239 at its outerlefthand armature opens the circuit for relay the test terminal 242 ofswitch K and sub- .stltutes a ground therefor, thereby, causing all themultiple contacts of all selector switches such as K to cause the seizedtrunk L to test busy. At its inner right-hand armature relay 239 causesrelay 246 to operate in an obvious circuit. Relay 246 in attracting itsarmatures connects the conductors of the connecting circuit through tothe trunk leading to the f rate quoting desk.

As a result of the operation of relay 246, a circuit is establishedwhich may be traced from grounded battery, through the armature and backcontact of cut-off relay 300, right-hand Winding of relay 301, ringconductor of the selected trunk leading to the rate quoting desk, ringterminal 290 and wiper 291 of switch K, front contact and lower armatureof relay 246, lower normal contacts of key 293, winding of relay 292,upper normal contacts of key 293, upper armature and front contact ofrelay 246, wiper 294, and tip terminal 295 of switch K, tip conductor ofthe selected trunk leading to the rate quoting desk, left-hand windingof line relay v301 to ground. Relays 301 and 292 operate in thiscircuit, the latter and theformer establishing a circuit from groundedbattery, front contact and righth'and armature of relay 301', throughthe lilainent of lamp 303, back contact and righthand armature ofslow-to-release relay 304 to ground. The illumination of lamp 303 inthis circuit indicates to the rate quoting operator that a call isawaiting her attention. The illumination of lamp 296 as hereinbeforedescribed serves as a guard signal to the recording operator.

The rate quoting operator in response to the illumination of lamp 303inserts plug P into jack J of the selected trunk, whereupon cut-offrelay 300 operates in an obvious sleeve circuit. Belay 300 opens thecircuit for line relay 301 and for relay 292 which thereupon releasecausing the darkening of lamps 303 and 296 respectively, thelatter'indicafing to the recording operator the response of the ratequoting operator.

- By actuating her talking key (not shown), the rate quoting operatormay converse with the calling subscriber. Assuming that the conversationhas ended, the rate quoting operator withdraws plug P from jack Jwhereupon relay 300 releases opening the circuit for relay 304 andclosing the circuit for line relay 301. Relay does not release sinceitis a slow-torelease relay and its locking circuit will be completedatthe left-hand armature and front contact of relay 301 before it has timeto retract its armatures so that the operator at position M does not geta false signal when she disconnects.

The circuit for. relay 292 is again established causing lamp 296 tobecome illun1iated to indicate to the recording operator I nection.

To release the connection the operator actuates a restoring key 262 thatis arranged, in a manner well known in the art, to restore any of thekeys 220, 225, 226 and 227, whichever one of these keys may be operated.Key 220 which in this instance is operated consequently releases andthereby causes relay 208 to restore thereby ren'ioving ground fromterminal 132 of switch S causing the release of relay 133. Relay 33 inreleasing, removes the shunt about the high resistance left-hand windingof relay 100 thereby causing the current in the circuit including thewinding of marginal re lay 25 to decrease to such an extent as to permit this relay to release. Relay 25 in retracting its armature causesrelay 60 to release. The release of relay 60 causes the opening of thecircuit of the reversing relay 14 and also of relay 63. Relay 63 inreleasing, causes the interrupter circuit including the winding of relay65 i? be. completed, it being understood that relay 67 remains 1 throughthe windings of polarized relay 91.

Relay 91 thereupon causes lainp 92 to flash as a dis-connect signal tothe semi-merchant cal operator.

The semi-mechanical operator, noting the flashing of lamp 92 removes theplug P fIOHL jack J of the calling line thereby restoring the callingline to its initial condition and causing the restoration of thedistrict selector switch 90. Following the restoration of switch 90, thecircuit previously traced through the winding of relay 13 is openedthereby opening the circuit for relays 16 and 15.. At its innerarmature, relay 16 opens the circuit for reversing relay 1%. Relay upondeenergizing, opens'the circuit for relay 19 which in turn opens thecircuit of relay 20 and since, at this time the auxiliary holdingcircuit of relay 20 previously traced over conductor ()1 is opened atthe left hand larinature and contacts of relay 60, relay 20deen'ergizes, opening at its right handarmature, the holding circuit forrelay-67 whichrelay in turn opens the circuit for relay 2 1a11d-re1n0ves busy ground potential from conductor 68 and themultipleterminals of the'toll'trunk. *The release of relay ,lOOashereinbetore mentioned causes relay lO lto release whereupon the lockingcircuit forrelay 109 is opened, so that this relay alsoreleases removingthe holding ground from the windings of relays 105 and'122. Relays 105and 122 there-upon release. Relay 122 at its lowermost armature opensthe circuit for relays 107 and 203 \vhereupon'these relays release, thelatter removing the busy ground potential from the test terminal 127 ofswitch S and substitutingtherefor battery 200. Relay 122 alsodisconnectsthe tip and ring conductorsof the recording trunk from the correspondingterminals letO and 141 of switch 53. 'Relay 15 upon deenergizing alsoopens the circuit previously traced through the winding of relay overthe toll trunk and through the windings o'f relays 100, 101

and 102 whereupon-these lastthree relays, it operated, release, relay'25 having been. previously released. The circuits'at the outgoingandincoming ends of the trunk are now in their normal positions.

Upon the release of key 220 at the recording operators position, ashereinbefore mentioned, relay releases removing key 211, whereuponrelayJBS 'SGlIll-IHQCll211116211 operator reconnects ground from thewinding of relay 223 and also from the group otterniinals 230 of switchK. Relay 223 thereupon releases, opening'tlie locking circuit torrelay23 1 and alsofor relays 239 and 2T0 which thereupon release. Thedeenergization of relay 270 removes thebusy condition 1 1O111tl18trunk'L leading to the rate quoting desk, and again connects'battery tothe test terininal 2 12 01 switch K to indicate the idle condition ofthe trunk. All the apparatus is now in its normal condition and thecircuits prepared to receive another call.

If in'the course of a connection, the recording operator at 0 shoulddesire to signal the semi-mechanical operator, she may do so bysuccessively actuating the flashing is intermittently deenergized toalternately remove and complete the shunt about the high resistancewinding 01? relay 100 so that the current in the circuit includingmarginal relay 25 will be varied causing this relay to follow the,actuations of key 211. The circuit for relay will thereupon beintermittently opened and closed to cause the circuit throughslowreleasing relay 63 and reversing relay 1% to be opened and closed atthe same rate. Relay 63, being slow-to-release, does not have suliicienttime to restore its ELITHZHJUIBS to their initial positions betweensuccessive deenergizaatons of relay '25, and therefore, the circuitswhich are established by relay 63 are maintained intact. lielay l thowever, responds to each deenergization of relay and at its armaturecontacts reverses the current flowing through the windings of polarizedsupervisory relay 91 at the senaianechanu cal operators position. Thelamp 92 which is controlled by relay 91 will, therefore, flash insynchronisni with the actuations of key 211.

In response to this flashing signal, the her telephone with thesemi-n1echanical cord and is then in a position to con'nnunicate withthe recording toll operator.

Should the originating or semi-mechanical operator desire to signal therecording operator, she may do so by momentarily ac tuating the hey k todisconnect the windings of polarized rel ay 91, from the cord andconnect battery and ground to the ring and tip conductors of the cordwhereui pon the battery-associated with repeating coil 12 is renderedineffective to hold relay 1.3 operated.

Relayls thereupon releases causing relays 16 and to deenergize. lit-clay15 causes the circuit tor relay 19 to be opened but relay 19 beingslew-to-release does not have su'tlicient time to retract its ari'natures. How- 6VG1,Sl1()Ul(l relay 19 restore and open the circuit forrelay 20 the slow-releasing characteristic of this relay would tend tomaintain it operated. The rhalzicteristics of reto the incoming end ofthe trunk. fore, in response to the actuation of key 7c, a v circuit forrelay 213 is established which may be traced from grounded battery, overthe front contact and lower armature of relay 13 1 inner lower armatureand front contact of relay 122, wiper 139, and terminal 1&1 of switch S,back contact and inner right-hand armature of relay 207, through thelefthand winding of relay 213, terminal 140 and wiper 138 of switch S,front contact and upper armature of relay 122, upper armature and frontcontact of relay 13 1, through the resistance element to ground. Relay213 operates in this circuit and in attracting its armature establishesan obvious circuit for the supervisory lamp 250 and locks itself toground on the outer right-hand arn'iature of relay 207. In response tothe illumination of lamp 250, the recording operator again actuates key210 to connect her head-set to the tip and ring conductors of the trunkand to establish an obvious circuit for relay Relay 207 thereuponoperates disconnecting the left-hand winding of relay 213 from the tipand ring conductors of the trunk and opening the locking circuit ofrelay 213. This relay thereupon releases causing the darkening of lamp250.

It for any reason, the rate-quoting operator should desire to recall therecording toll operator, she may do so by successively withdrawing andinserting plug P into jack J. This action causes relay 300 tobesuccessively deenergized, and to thereby successively disconnect batteryfrom the righthand winding or" relay 301, which relay together withrelay 292 are bridged across the tip and ring conductors of the trunk.Relays 292 and 301, therefore, follow the interruptions of the bridgecircuit caused by the intermittent actuations of sleeve relay 300. Lamp296 which is controlled by relay 292, therefore, flashes in synchronismwith the connections and disconnections of plug P with jack Q It will benoted, however, that lamp 303 which is controlled by line relay 301 doesnot flash at this time since its circuit will be maintained opened atthe back contact and left-hand armature of slow-to-release relay 304during this period, relay 1 remaining energized owing to itsslow-release characteristic,

The ringing key 298 which is furnished with the recording operatorsequipment is supplied for the purpose of signaling a special operatorwhose position may be equipped with a ringdown type of signalingequipment.

. The previous description was directed to a call originated by asubscriber who is entitled to regular toll service. If, however, asubscriber other than the subscriber at station A who is entitled tosome other class of service, should initiate a call, the semi-mechanicaloperator would set up a special code, which would cause the brushesassociated with her semi-mechanical cord circuit to come in contact witha. ditierent set of trunk terminals such as a, b or c. Depending-onwhich of these terminals are employed in the establishment of aconnection, currents ofdifierent strengths and polarities aretransmitted over the recording trunk from the sources and 99 to effectthe operationot relays 100, 101 and 102 in various combinations.Depending upon the combination of relays operated, currents from thesources 114 and 190 are sent out through resistance elements 115, 116,151 and 152 over the outgoing end of the trunk to the recording tolloperators position to efl'ect the operation 01' relays 214i, 215 and 216in various combinations, and depending upon these combinations effected,one of the class of service signal lamps 257, 256, 255 and 219 will beilluminated, the variously marked caps of which will indicate to therecording operator the class of service to which the calling subscriberis entitled. That is, the class of service to which each subscriber isentitled is indicated by a particular figure or sign on the capsilluminated by the corresponding lamps.

Referring now to Fig. at taken in connection with Figs. 2 and 3, asubscriber at substation B on initiating a. call removes the receiverfrom the. switchhook whereupon a circuit is established for line relay400, this circuit extending over the subscribers line loop. Relay 4:00operates in this circuit and establishes an obvious circuit for linelamp 102. The lamp 102 is provided with a distinctive lamp cap whichdesignates the class of service to which the calling subscriber isentitled. In response to the illumination of lamp 402 the A operatorinserts plug P of of jack J, and plug P upper left-hand winding ofrepeating coil 405 to ground. Supervisory relay 404 operates in this carcausing the darkening of lamp 402.

The r-i operator 'llO'W aetuates key 410 in order to connect hertelephone set with the talking strands of the cord circuit. The operatornow learns from the calling subscriber the nature of the desired'connection. It will be assun'ied, as in the previous case, that thecalling subscriberdesires a connection with therecording toll operator.

The A operator tests for an idle recording trunk in the 'well-knoivnmanner. Assuming that the trunk-L is the first idletrunk encountered andthatthe calling subscriber is entitled to the-class of servicecorrespond ing to jack J the operator will insert plug P into this itClIJ whereupon a circuit is established which may be traced from groundedbattery through the filament of lamp 408, sleeve contacts of plug 1, andjack J -,,-Wind1ng of relay 500, conductor 520, left-hand armatureand-back contact of-relay 501, resistanceelement 502 to {ground The lamp"108 energizes in this =circuit'an'd servesas a guard signal totheAcpera-tor. Relay 500 also operates in this circuit and in attractingits innerarinature performs no iiul'nediate function. However, at itsouter armature, relay 500 establishesacircuit extending fromgrounded-battery 503, through the resistance element 504, outer armatureand front contact of relay 500, conductor 50.3, winding of marginalrelay 506, back contact and lower armature of relay 507, lower lefthandWinding of repeating coil 103, windings of polarized relay 102, marginalrelay 101 and relay 100, upper lefthand windingof repeatingcoil 103,upper armature and back contact of relay '507 to ground. The current inthe "circuit just traced is of such strength as toqprevent marginalrelay506'fr0m'energizing at this time, but of sufficient strength andproper polarity to-cause relays 100 and 101 to operate. Relay 100 inoperating establishes an -ob- YlOUS circuit for relay 104:. Relay 101 inoperating establishes an obvious circuit for relay 117.

it its outer armature, relay 104 establishesan obvious circuit for relay105; at its inner armature relay 10lcauses the energization of relay12toconnect the tone source 113170 the tip and ring-conductorsofthetrunk in order to indicate to the calling subscriber that the recordingoperator is being signaled. ltelay 117 and relay 105 in operating bothlock up to 'ground on the outer armature of relay 104 by Way' of thenormal right-hand contacts of relay 109. As a-result oftheenerg-izat-ion-of relays 117 and 105, a circuit now exists extendingfrom grounded battery 11%, through resistance element 115, front contactand outer right=hand armature of relay 117, conductor 118, back contactand right-h-aml armature of relay 11-9, conductor 120, right-handarmature and front contact of relay 105,001 1ductor121 to-th'e midpointof the right-hand windings of repeating coil 103 and thence over thetipand ring conductors ofthe incomingend of the recording trunk as farasthe upper andlower inner armatures of --relay-122. Itis believedunnecessary to repeat the pperations which extend the incomingend of thetrunlgcircu-it to the --recomli-ng operatorls position 0 since thesesteps were described in detail-in the previous description. HoWeVeTr, itwill be assumed that the lamp 209 -hasbeen illuminated as a signal-tothe recording-operator and she has responded tothe call by actuatingtalkinglreyQlO,

11s a result -0f the actuation of talking key 2 10, relay 207 isoperated for the par-- poseshereinbefore mentioned, One effect of theoperation of relay 207 is to connect ground to "the terminal 1320fswitch-S by Way of conductor 21-2 Thisground causes relay 133 to operateWhich in attracting its right-hand armature performs the samefunction-as it did in the preceding case. In attractingits left handarmature, relay 133 again shunts the high resistance left-hand Windingof relay 100 so that the current in the circuit including marginalrelay500, previously traced, is increased suflieiently to permit relay506 to operate. Relay 606 in operating establishes an obvious circuitfor relay '508 Which thereupon operates and locks itself to ground onthe-inner -=a11nature of relay -500, at its right-hand armaturerelaytOS'establishes'an obvious circuit for relay 507 which in operatingdisconnects the circuit including the marginal relay 506 fromthe trunkcircuit and bridges'the condensers510 and 51 1 sothat acireuitmow'existswhich may be traced from igrounded battery through lower right-handWinding of repeating coil 405, Winding of relay 406, ring'contacts ofplug P and jaclrJ front contact and lower armature of relay 507, lowerleft-hand Winding of "repeating coil 103, windings-of polarized relay102, marginal relay=101,'righthand Winding of relay 100, left-handarmature and front contact of relay'133, upperleft hand Winding ofrepeating coil 103, "upperarmature and front contact of relay 507,Windingof marginal relay 509, tip contacts of \jack J and plug P throughthe upper right-hand Winding ofrepeating cell 405 to ground. Relays'106and 509 operate in this circuit, the former shunting out the lamp 408 asan indication to the A operator that the recording operator hasresponded to the call, while the latter establishes an obvious circuitfor relay 512. Relay 512 in operating shunts the resistance element 502and the right-hand winding of relay 501 so that relay 501 energizes overthe sleeve circuit through its lefthand winding to ground on thealternate contacts of relay 512. Relay 501 in energizing in the sleevecircuit prepares a peremptory disconnect signaling circuit which will becompleted hereinafter.

As a result of the actuation of talking key 210 at the recordingoperators position O, and as a result of the extension of the trunkcircuit as far as the recording operators posit-ion, the circuit whichwas previously traced from grounded battery 114 as far as the upper andinner lower armatures of relay 122 is now completed over the wipers 188and 189 and terminals 140 and 141 of the selector switch S, over theupper and middle alternate contacts of key 210 through both simplexwindings 217 and 218 through the windings of relay 214, marginal relay215 and polarized relay 216 to ground. The current in this circuit issuch as to cause only relays 214 and 215 to operate, so that a circuitmay now be traced extending from grounded battery through the filamentof lamp 255, front contact and left-hand armature of relay 215, backcontact and armature of relay 216, armature and front contact of relay214 to ground. lhe lamp 255 energizing in this circuit indicates to therecording operator the class of service of the calling subscriber.

WVhen the recording operator actuates key 210, her telephone isconnected across the main conductors of the trunk so that she mayconverse with the calling subscriber to ascertain the nature of thecall. It will be assumed that the calling subscriber requests aconnection with information, whereupon the recording operator actuatesthe key 225 at her position which is designated information. She alsorestores her talking key 210. As a result of the actuation of key 225,relay 208 operates as in the previous connection. At its lower alternatecontact, key 225 establishes an obvious circuit for relay 260 whichcorresponds to relay 222 in the previous description. At its outerrighthand armature relay 260 establishes a circuit for a relay similarto relay 223, whereas at its inner armature it connects ground to theconductor 261, leading to the group of terminals 265 of sector 228 ofswitch K, which group is allotted to information.

As in the preceding connection, the stepping magnet 231 causes thewipers of switch K to advance over the terminals until, in thisinstance, the grounded group of terminals 265 is reached, whereuponsimilar operations as described in connection with the rate quotinggroup 230 are performed, so that the selector switch K hunts for an idletrunk leading to the information operators desk.

The remaining operations which take place in the case of a call forinformation are similar to those described in connection with the calldescribed for the rate quoting operator so that these operations neednot be repeated. However, the manner in which a disconnect signal isgiven to the A operator differs and this operation will now bedescribed. The recording operator at the termination of the connection,actuates the re store key 262, whereupon key 225 is released. Therelease of key 225 deenergizes relay 208 whereupon ground is removedfrom the winding of relay 133 so that this relay releases, removing theshunt from the high resistance left-hand winding of relay 100. Theremoval of this shunt causes the current in the circuit includingmarginal relay 509 to decrease to such an extent as to deenergize thisrelay. The deenergization of relay 509 removes ground from the windingof relay 512 whereupon this relay releases so that the circuit forinterrupter 515 is now completed. The reduction of current in the abovementioned circuit also causes relay 406 in the A operators cord torelease. The operation of the interrupter 515 causes relay 516 tointermittently attract and release its armature so that the sleevecircuit including the lefthand winding of relay 501, winding of relay500 and the filament of lamp 408 is intermittently opened so that thelamp 408 flashes synchronism with the interruptions caused by theinterrupter 515.

The A operator upon noting the flashing of the lamp 408 proceeds to takedown the connection by withdrawing plug P from jack J whereupon relays500 and 501 release. The release of relay 500 opens the locking circuitfor relay 508 which in turn releases relay 507, restoring the outgoingend of the recording toll trunk to normal. In withdrawing the plug Pfrom jack J the circuit for sleeve relay 401 is opened whereupon theline relay 400 is again connected to the conductors of the subscribersline in preparation for another call. The release of the remainingapparatus is effected in the same manner as described in the precedingdescription.

Keys such as 205 at the recording operators position are provided in theleads from the armatures of the relays 204 of the connecting circuits atthis position so that when the position is unattended these keys will beactuated to place a busy potential on all test terminals such as 127 ofconnecting circuits leading to these positions and thereby rendering theposition unavailable to incoming calls. Keys such as 241 serve the samepurpose for the trunks leading to the special operators desk.

WVh-at is claimed is:

1. In atelephone system, a trunk circuit terminating in a plurality ofterminals, an operators position, a group of connecting circuitsterminating in keys at said position, a signaling device at saidposition for each of said trunk terminals, means responsive to theseizure of said trunk by Way ofone ot saidterminals for selecting anidle one of said connecting circuits, and means l8SPO1l sive to theactuation of one of said keys at said position for actuating the signalidevice corresponding to the trunk terminal taken for use.

2. In a telephone system, a trunk circuit terminating in a plurality ofterminalsan operators position, a signaling device thereat, a pluralityof connecting circuits terminating in keys at said position, meansresponsive to the seizure oi said trunk by way of one of said terminalsfor associating said trunk with an idle one of said connecting circuitsand operating said signaling device, indicating means at said positioncorresponding in number to said trunk terminals, and means responsive tothe actuation of one of said keys for operating the indicating meanscorresponding to the trunk terminal taken for use.

(3. In a telephone system, atrunk circuit terminating at its outgoingend in a plurality of terminals, an operators'position, a plurality ofconnecting; circuits terminating at said position in keys, asignalingdevice for each of said connecting circuits, means responsive to theseizure of: said trunk by way oi one of said terminals for automaticallyconnecting the incoming end of said trunk with an idle one of saidconnecting circuits to cause said signaling device to be actuated,indicating means at said position corresponding in number to theterminals of said trunk, and means responsive to the ae tuation of oneof said keys for restoring said signaling device to normal and actuatingthe indicating means corresponding to the trunk terminal taken for use.

l. in a telephone system, a trunkcircuit,

first and second operators positions, a plurality of connecting circuitsterminating at said first position in keys, a switch for said connectingcircuits, means responsive to the seizure of said trunk for causing saidswitch to hunt for and connect said trunk with an idle connectingcircuit and extend said trunk to said first position, and meansresponsive to the actuation of one of said keysat said lirst positionfor extending the selected connecting circuit to said second position.

In a. telephone system, a trunk'circuit, a first operators position, asignaling device thereat, a second operatonsposition a sigtion of oneots-aid keys tor eirtending the selected connecting circuit tosaidsecond operators position and actuating the signaling device there-at.

(i. In a telephone system, a trunk circuit terminating in aplurality .oitern'iinals,an

operator's position, a group ;oi connecting circuits terminating in keyslat said position, a signaling device'at said position for each of saidtrunk terminals, means responsive to the seizure of said trunk by way ofone of said terminals tor selecting zone of said connecting circuits andextending said trunk to said position, means responsive to the actuationof one 01": said keysat said position for actuating the signaling devicecorresponding to the trunk terminal taken for use, a second operatorsposition, and means responsive to the actuation ofanother of said keysfor extending the selected connecting circuit to said second position.

7. In a telephone system, a trunk circuit terminating in a plurality ofterminals,an operators )osition, a signaling device there at, a plurzity of connecting circuits'terminating in keys at said position, meansresponsive'to the seizure ot-said trunk by way of one of said terminalsfor associating said trunk with an idle one oi said connecting circuitsand operating said signaling de vice, indicating means at said positioncorre sponding in number to saidtrunk terminals, means responsive to theactuation of one of said keys for operating the indicating meanscorresponding to the trunk terminal taken for use, a second operatorsposition, a signaling device thereat, and means responsive to theactuation of another oi? said keys for extending a selected connectingcircuit to said second position and actuating said signaling device.

8. In a telephone system, a trunk circuit terininating at its outgoingend in a plurality of terminals, an operators position, a pluralityot'connecting circuits terminating at said position in keys, a signalingdevice for each of said connecting circuits, means re sponsive to theseizure of said trunk by Way of one of said terminals for automaticallyconnecting the incoming end of said trunk with an idle one of saidconnecting circuits to cause said signaling device to be actuated,indicating means at saidpositioncorresponding in number to the terminalsof said trunk, means responsive to the actuation of one of saidkeys forrestoring saidsignaling device nae to normal and actuating theindicating means corresponding to the trunk terminal taken for use,a'second operators position, a signaling device thereat and meansresponsive to the actuation of another of said keys for extending theselected connecting circuit to said second position and actuating thesignaling device thereat.

9. In a telephone system, a trunk circuit terminating in a plurality ofterminals, a first operators position, a connecting circuit terminatingin keys at said position, a signaling device at said position for eachof said trunk terminals, means responsive to the seizure of said trunkcircuit by way of one of said terminals for extending said trunk circuitto said first position by way of said connecting circuit, meansresponsive to the actuation of one of said keys for operating thesignaling device corresponding to the trunk terminal taken for use, asecond operators position, and means responsive to the actuation ofanother of said keys for extending said connecting circuit to saidsecond position.

10. In a telephone system, a trunk circuit terminating in a plurality ofterminals, a first operators position, a connecting circuit terminatingin keys at said position, a signaling device at said position tor eachof said trunk terminals, a selector switch responsive to the seizure ofsaid trunk circuit by way of one of said terminals for seizing saidconnecting circuit and extending said trunk'circuit to said firstposition by way of said connecting circuit, means responsive to theactuation of one of said keys for operating the signaling devicecorresponding to the trunk terminal taken for use, a second operatorsposition, and a selector switch responsive to the actuation of anotherof said keys for extending said connecting circuit to said secondposition.

11. In a telephone system, first and second operators positions, a trunkcircuit, a plurality of connecting circuits terminating at said firstposition in a plurality of keys, means including a switch associatedwith said trunk and responsive to the seizure of said trunk at itsoutgoing end for causing said switch to hunt for and connect said trunkwith an idle one of said connecting circuits to extend said trunk tosaid first position, a group of trunks leading to said second position,and means responsive to the actuation of one of said keys for selectingan idle one of said group of trunks and extending the selectedconnecting circuit to said second position.

12. In a telephone system, a trunk circuit, a primary operatorspositions, a group of connecting circuits terminating in keys at saidprimary operators position, a switch responsive to the seizure of saidtrunk for hunting for and connecting said trunk with an idle-one of saidconnecting circuits to extend said trunk to said primary operatorsposition, secondary operators positions corresponding in number to saidkeys, groups of trunks, each group serving a corresponding secondaryposition, a switch associated With each connecting circuit and in whichall of said groups of trunks terminate and means responsive to theactuation of one of the keys in the selected connecting circuit foroperating the corresponding switch to select a group of trunkscorresponding to the actuated key and seize an idle trunk in that groupwhereby said connecting circuit is extended to the secondary positioncorresponding to the key actuated.

18. In a telephone system, a trunk circuit, primary and secondaryoperators positions, a plurality of connecting circuits terminating atsaid primary position in keys, said keys corresponding in number to saidsec-- ondary positions, means responsive to the seizure of said trunkfor selecting one of said connecting circuits and extending said trunkto said primary position, a group of trunks serving said secondarypositions, said group being divided into sub-groups and each sub-groupserving a particular secondary position, a switch associated with eachconnecting circuit in which all of said subgroups of trunks terminate,means responsive to the actuation of one of the keys ot the selectedconnecting circuit for actuating the corresponding switch for theselecting of the corresponding sub-group oi trunks and for seizing anidle trunk in said group whereby the selected connecting circuit isextendedto the secondary position corresponding to the key actuated.

14. In a telephone system, a trunk circuit, first and second operatorspositions, a group of connecting circuits terminating in keys at saidfirst operators position, means responsive to the seizure of said trunkfor selecting one of said connecting circuits and extending said trunkto said first operator-s position, means responsive to the actuation ofone of said keys for rendering said first operators positioninaccessible to calls incoming over the remaining connecting circuitsand means responsive to any one of the remaining keys for extending theselected connecting circuit to said second operators position.

15. In a telephone system, a trunk circuit, first and second operatorspositions, a group of connecting circuits terminating in keys at saidfirst opera-tors position, means responsive to the seizure of said trunkfor selecting one of said connecting circuits and extending said trunkto said first operators position, means for causing said first operatorsposition to test busy to calls incoming over the remaining connectingcircuits when the first call is answered and means responsive to theactuation of one of said keys for extending the selected connectingcircuit to said second operators position.

16. In a telephone system, a trunk circuit, first and second operatorspositions, a signaling device tliereat, a group of connecting circuitsserving said first operators position and terminating thereat in aplurality of keys, means responsive to the seizure of said trunk forselecting one of said connecting circuits and extending said firstoperators trunk circuit to said position whereby the signaling devicethereat is actuated, means responsive to the actuation of one of saidkeys for disabling said signaling device and for rendering said positionbusy to the re maining connecting circuit as long as said key isactuated and means responsive to any one of the remaining keys forextending the selected connecting circuit to said second operatorsposition.

17. In a telephone system, a plurality of classes of telephone lines, atrunk circuit terminating at its outgoing end in as many terminals asthere are classes of lines, an operators position, means thereatresponsive to a call incoming over one of said lines for indicating theclass of service of the calling line, switching means at said positionfor connecting the calling line with said trunk by way of the terminalcorresponding to the class of the calling line, a second operatorsposition, a signaling device thereat for each of said classes oftelephone lines, a group of connecting circuits serving said secondoperators position and terminating thereat in keys, means responsive tothe actuation of the aforesaid switching means for selecting one of saidconnecting circuits and extending said trunk to said second position,means responsive to the actuation of one of said keys for connectingsaid signaling devices with the selected connecting circuit whereby thesignaling device corresponding to the class of the calling line isoperated, a third operators position, a group of trunks serving saidthird operators position, and means responsive to the actuation ofanother of said keys for selecting one of said trunks and extending theselected connecting circuit thereover to said third position.

18. In a telephone system, a trunk circuit: terminating in a pluralityof terminals, operators positions, connecting circuits terminating inkeys at said positions, a signaling device at each of said positions foreach of said trunk tern'iinals, means responsive to the seizure of saidtrunk circuit by Way of one of said terminals for selecting one of saidconnecting circuits, and means responsive to the actuation of one ofsaid keys associated with the selected connecting circuit for actuatinga signaling device corresponding to the trunk terminal taken for use.

19. In a telephone system, trunk circuits, first and second operatorspositions, a plurality of connecting circuits terminating at said firstoperators position, a plurality of keys associated with each connectingcircuit, an individual switch associated with the incoming end of eachtrunk circuit for connccting an idle one of said connecting circuitsthereto operative in response to the seizure of a trunk circuit at itsoutgoing end, a telephone circuit at said first operators position,means for associating said telephone circuit with any one of saidconnecting circuits, means for preventing the selection of anyconnecting circuits by any of said switches operative in response to theconnecting of the telephone set to any one of said connecting circuits,and means responsive to the actuation of any one of said keys of aselected connecting circuit for extending it to said second operatorsposition.

In testimony whereof, we have signed our names to this specificationthis 14th day of November, 1923.

JOHN F. TOOMEY. HENRY EVPHELP'S.

